Multiplying lever for indicating displacement



Nov. 15, 1955 Filed Dec. 23, 1952 MULTIPLYING LEVER FOR INDICATINGDISPLACEMENT Raymond Howard Griest, Los Angeles, Calif., assignor, bymesne assignments, to Hughes Aircraft Company, a corporation of DelawareApplication December 23, 1952, Serial No. 327,555

Claims. (Cl. 73432) This invention relates to mechanical indicatingmechanisms, and more particularly to a lever of the multiply ing typesuitable, for example, for obtaining relatively large indications ofsmall motions of a movable or vibratory body.

It has been found desirable in many instances to provide mechanicalmechanisms suitable, for example, for indicating the effect on delicateparts, such as electrical measuring instruments, of vibratory motion ofa structure which supports such instruments. Such an indicatingmechanism may be employed, for example, to obtain data which may be usedto determine how the mounting of the structure may best be modified toinsure minimum vibrational movement thereof. Such an indicatingmechanism may also be employed to respond to physical movements of suchdelicate instruments by developing damping forces substantiallyinstantaneously upon the occurrence of such movements to react upon theinstrument thus reduce or damp undesired motions to a minimum. It isnecessary, under such circumstances, that the means employed formagnifying such small mechanical motions be free from backlash.

The present invention specifically relates to a simple leverconstruction including a pointer which will have angle and has its endssecured to the opposite ends of the Web of the channel-shaped element.Upon motion of the movable structure within the plane of the flaredportion of the flange affixed thereto, the portions of the flangesextending between the web and the flared portions will be distorted soas to permit the web to rotate. The pointer moves with the Web and itsintermediate portion moves over a relatively large distance compared tothe movement of the movable structure.

It is, therefore, an object of this invention to provide an extremelysimple lever of the multiplying type capable of magnifying small motionsof a portion thereof without backlash.

It is another object of this invention to provide a multiplying typelever comprising a pair of spaced, parallel, flexible elements adaptedto be secured, respectively, to a movable structure and to a fixedstructure, means providing mechanical linkage between the flexibleelements, and a pointer element affixed to such linkage means andadapted to move through a relatively great distance in response to smallmotions of the movable structure with respect to the fixed structure.

multiplying lever having a minimum number of component parts which is ofsimple construction and capable of reliable operation for accuratelymagnifying small motions of certain portions thereof.

The novel features which are believed to be characteristic of theinvention, both as to its organization and method of operation, togetherwith further objects and advantages thereof, will be better understoodfrom the following description considered in connection with theaccompanying drawing, in which different embodiments of the inventionare illustrated by and the scope of the invention is pointed out in theappended claims. In the drawing:

It is a further object of this invention to provide a Fig. l is aperspective view of a simple lever construction in accordance with thisinvention;

Fig. 2 is a top plan view of the lever of Fig. 1;

Fig. 3 is a perspective view similar to Fig. 1, showing the action ofthe lever of the invention in response to a motion of a portion thereof;

Fig. 4 is a top plan view of the lever in the position shown in Fig. 3;

Fig. 5 is a top plan view of the lever of Fig. l, in an arrangement toillustrate a practical use of the indicator of this invention;

Fig. 6 is a perspective view of a modified version of the lever of Fig.1;

Fig. 7 is an exploded view showing the elements comprising the lever ofFig. 6; and

Fig. 8 is a side elevation view of the lever of Fig.

illustrating its position in response to a small motion of a movablebody to which it is connected.

Referring to the drawing, in which like reference characters indicatelike elements throughout, and more particularly to Figs. 1 and 2, apreferred embodiment of the multiplying lever of this inventioncomprises a flexible, channel-shaped member 16 having flanges 12, 14extending perpendicularly to or at right angles from a flat web orcenter portion 16. The channel member 10 may be formed from a sheet ofany suitable flexible material, such as Phosphor bronze. The flanges 12,14 have flared ends shown, by way of example, as flat, flared sections18, 20 which flare or extend outwardly from the parallel portions offlanges 12, 14 in a common plane parallel to web 16. Aflixed to theopposite ends of web 16 is a pointer element 24. Pointer 24 preferablycomprises a Wire that is bent in an acute angle at its center. The wirehas its free ends aflixed to web 16 in a suitable manner, such as bysoldered connections provided at points 26, 28 at the corner between web16 and flange 14. The pointer element could, of course, comprise atriangular sheet element having its base aflixed to web 16.

As indicated in Figs. 1 and 2, the flared sections 18, 2t) of flanges12, 14 are adapted to be aflixed, respectively, to a fixed structure 30and to a movable structure 32. As indicated by an arrow 33, movablestructure 32 is adapted for movement in opposite directions in the planeof flared section 20 and parallel to the edge of web 16. As will beexplained more fully hereinafter in connection with Figs. 3 and 4, thepointer 24, by virtue of the construction of the lever above described,Will be moved in a plane parallel to flared section 20 and through aconsiderable angle in response to very small motions of movablestructure 32.

As will become more evident hereinafter, the flared sections 18, 20 areunnecessary to obtain Wide move ments of pointer 24 which correspond torelatively small motions of movable structure 32 in the manner abovedescribed. For example, flared sections 18, 20 could be eliminated andthe free ends of flanges 12, 14 ex-' tending perpendicularly from web 16could be secured, as by soldering, to the respective structures 30, 32.

Figs. 3 and 4 illustrate the effect of motion of structure 32 through adistance a in the direction indicated by Patented Nov. 15, 1955 Way ofexample only,

arrow 34, and in the plane of section 20. From their undistortedposition, shown in dotted lines, the flanges 12, 14 tend to twistclockwise at their front ends and counterclockwise at their rear ends.The flanges 12, 14 remain substantially parallel, however, while the web16 and the transverse center line 36, which passes through the vertex orpointer end of pointer 24, rotate counterclockwise about an axis normalto the plane of the web. As indicated, for a motion of structure 32 inthe direction of arrow 34, which motion is counterclockwise withreference to the aforementioned center line, web 16 and pointer 24 alsorotate counterclockwise. The actions above described are opposite formotions of movable structure 32 opposite 'to arrow 34.

It can be shown that for very small motions of movable structure 32 overa distance d, with respect to reference structure 30, and for a web 16having a width w that is great compared. to the distance d, the free endof pointer 24 swings through an angle given by:

sin 0: 10

Furthermore, for extremely small distances d, it may be assumed that sinawe and hence:

Therefore, the movement of pointer 24 accurately corresponds to thedistance d through which movable structure 32 moves. The movement ofpointer 24 magnifies the motion of movable structure 32 by a factordependent upon the distance d. The distance through which the end ofpointer 24 moves in response to a corresponding movement of structure 32through distance d depends upon the distance of the end of pointer 24from web 16. Thus, with a sufficiently long pointer 24, sufiicientlylarge movements may be obtained which may be easily measured, in asuitable manner, to determine the extent of the motion of structure 32with respect to reference structure 3%. Fig. illustrates a preferredarrangement for obtaining an accurate measure of such movements.

Referring now to Fig. 5, the end of pointer 24 is employed as a slidingcontact for a potentiometer resistor 40, which preferably is curved tocorrespond to the are through which the pointer moves. The opposite endsof resistor 40 are connected to the positive and negative terminals of asuitable direct-current voltage source 42. The junction of thepotentiometer resistor 40 and the negative terminal of source 42 may beconnected to a point of reference potential, which is indicated asground. An output voltage lead 44 is connected to pointer 24.v Uponmovement of pointer 24 in response to movements of structure 32 in themanner previously described, varying voltages are developed betweenvoltage lead 44 and ground which accurately represent the deviation ofpointer 24 and the motion of structure 32 from a fixed referenceposition. Accordingly, voltage indications of the movement of structure32 are provided which may be utilized in a desired manner, for example,to provide a measure of the motion of structure 32 for test purposes inthe manner previously indicated.

A second embodiment of a multiplying lever of the invention isillustrated in Figs. 6 through 8. Referring now to Figs. 6 and 7, arigid I-beam member 50, which consists of an elongated web portion 51and a pair of substantially cubical flanges 53, 55 at the opposite endsof web 51, provides support for a pair of flexible members 52, 54.Flexible members 52, 54 are equal in length to l-beam member 50 andextend between flanges 53,. 55 on opposite sides of elongated web 51thereof. Flexible members 52, 54 are suitably secured at their ends tothe flanges 53, 55 as, for example, by suitable fastening means inaligned openings, so as to extend parallel to the web 51 of the beam 50,in the manner indicated in Fig. 6. A pointer 24 is affixed at its endsto the flanges 53, 55 so as to extend perpendicularly from flexiblemember 54.

Centrally located between the ends of flexible member 52 are oppositelyextending or transverse finger sections 56, 57; similarly providedintermediate the ends of flexible member 54 are oppositely extendingfinger sections 58, 59.

Referring now to Fig. 8, which illustrates the motion or distortion ofthe lever of Figs. 6 and 7, finger sections 56, 57 are afiixed to areference or fixed structure 62 and the finger sections 58, 59 areaflixed to a movable structure 64. Upon motion of movable structure 64in the plane of finger sections 58, 59 of flexible member 64, asindicated by arrow 65, flexible members 52, 54 are distorted. Thisdistortion takes the form of counterclockwise twisting of the portionsof flexible members 52, 54 intermediate the respective finger sections56, 57 and 58, 59 and the flanges 53, 55, so as to permit I-beam member50 to turn slightly (counterclockwise in Fig. 8). In the mannerdescribed previously in con nection with Figs. 2 and 3, the movement ofpointer 24 magnifies the relatively small motion of movable structure64. Hence, pointer 24 moves through an angle 0 in response to motions ofmovable structure 64 through small distances d.

What is claimed is:

l. A multiplying lever comprising, in combination, a flexiblechannel-shaped member comprising a web portion extending between a pairof parallel flanges, a pointer element comprising a stiff wire bent atits center to form 7 an acute angle, the ends of said wire being securedto opposite ends of said web portion and being disposed on oppositesides of a center line of said pohiter, said pointer extending apredetermined distance from said web portion and in the plane thereof,said flanges being flexible, said flanges distorting upon a smallmovement of the free edge of one of said flanges parallel to and withrespect to the free edge of the other of said flanges, said web portionrotating in a plane parallel to the path of movement of said free edgeof said one of said flanges, said pointer rotating with said webportion, free end of said pointer moving through a distance that is apredetermined multiple of the small movement of the free edge of saidone flange.

2. The lever defined in claim 1, in which said flanges extendperpendicularly from said web portion, and said flanges are coextensive.

3. The lever defined in claim 2, in which said flanges have flaredterminal sections adapted for connection, re spectively, to a referencestructure and a movable structure, whereby small motions of the movablestructure with respect to the reference structure and parallel to theflared section secured to the reference structure are magnified apredetermined amount by said pointer.

4. A lever arrangement comprising, in combination, a channel-shapedflexible member, said member having a rectangular web and a pair ofparallel, coextensive flanges, said flanges extending from oppositeedges of said web, said web having a predetermined width, a pointercomprising a length of stiff wire bent at its center, said pointerhaving its ends affixed to said web at its opposite ends, said flangesdistorting upon the free edge of one of said flanges moving through apredetermined small distance parallel to and with respect to the otherof said flanges, Lsaid flanges upon distorting permitting said web andsaid pointer to rotate through an angle substantially equal to the ratioof said predetermined distance to said predetermined width.

5 The lever defined in .claim 4, in which the bent center portion ofsaid pointer forms the sliding contact of a potentiometer, and a sourceof direct-current voltage, said source connected across saidpotentiometer, said pointer, upon relative movement between saidflanges, being moved along said potentiometer, whereby a voltagerepresentative of said motion exists at said pointer.

UNITED STATES PATENTS Bristol May 23, 1899 Trumpler May 6, 1930 AllerDec. 6, 1938 FOREIGN PATENTS Great Britain Nov. 6, 1919

